i changed the last step to return (n == ~0);
Best Regards
Ashish Goel
"Think positive and find fuel in failure"
+919985813081
+919966006652
On Fri, May 18, 2012 at 11:27 AM, Vishal Thanki <vishaltha...@gmail.com>wrote:
> On Sat, Apr 7, 2012 at 11:24 AM, Dave <dave_and_da...@juno.com> wrote:
> > @Ashgoel: Try this:
> >
> > bool OnesZerosOnes(unsigned int n)
> > {
> > if( !(n & 1) || !(n &= n+1) ) return 0;
> > n |= n-1;
> > return !(n & (n+1));
> > }
> >
> > Here is how it works:
> >
> > !(n & 1) is true if the number has trailing zeros.
> >
> > If the number has trailing ones, n &= n+1 replaces the trailing ones with
> > zeros.
> >
> > !(n &= n+1) is true if there are only trailing ones, i.e., the original
> > number was zeros followed by ones.
> >
> > n |= n-1 replaces trailing zeros with ones. Thus, if the original number
> is
> > ones followed by zeros followed by ones, the zeros have been changed to
> > ones.
> >
> > (n & (n+1)) replaces the trailing ones with zeros. If the number is now
> > zero, the number is valid, otherwise the number is invalid.
> >
> > Dave
> >
> >
>
> Superb, Dave!!
>
> > On Tuesday, April 3, 2012 7:00:36 PM UTC-5, ashgoel wrote:
> >>
> >> verify that the bits of a number are in format 1s followed by 0s
> followed
> >> by 1s like 1110001 is valid but 100100100 is not
> >>
> >> Best Regards
> >> Ashish Goel
> >> "Think positive and find fuel in failure"
> >> +919985813081
> >> +919966006652
> >
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